1. Field of the Invention
The Internet and the diversity and wealth of HTML-based Internet content available makes it desirable to exploit such content. The invention relates to a system and method by which HTML-based content is processed and distributed to a client in a manner which facilitates its delivery to the client.
2. Description of the Related Art
The most common mechanism to access Internet content today is through the use of a personal computer. Much of that Internet content is accessible as or via HTML-based (Hypertext Markup Language) Web pages. To access this content a user generally uses a personal computer ("PC"), for example, an Apple Macintosh or a PC running Microsoft Windows. In general, these PCs are configured with fast processors such as PowerPCs or Intel Pentium microprocessors and large amounts of memory. This level of hardware is necessary to effectively run today's resource intensive and full-featured Web browsers, like Netscapes Navigator, which processes the HTML-based Web page into a graphical screen capable in interacting with the user and Web servers. These PCs are connected to the Internet (and ultimately a Web server) usually via an ISP or online service using a modem line or a high-speed data link (symmetric or asymmetric), like a T1 (1.5 megabits per second) or T3 (45 megabits per second). These modem lines or high-speed data links are necessary due to the large amounts of data being transferred to the PC.
Communications over the Internet require that the PC has two-way, interactive, communications with the Internet content server. In the case of Web browsers, for example, the browser (running on a PC) initiates a request to a Web server for content (via a "return channel"). The Web server responds by sending the requested content, usually in HTML, to the browser (via a "forward channel"). The browser receives the HTML data, processes it and displays the Internet content as a graphical Web page to the user. Often these Web pages have hyperlinks embedded in the Web page which allow the user to request further Internet content. These hyperlinks are "addresses" or Uniform Resource Locator (URL's) which tell the browser where to find the content. By selecting a hyperlink, the user tells the browser to send a request to the computer hosting that Web page for that content or to jump to another section of a Web page.
Given the expense and complexity involved in purchasing and using a PC not all households have a PC. Even households that have PC may not have an Internet account due in part to costs and the inconvenience of tying up a telephone line during an online session. In contrast, most households today have television sets connected to receive cable services or wireless broadcasts and more advanced systems are moving toward a fully digital video broadcasting system, and thus may be used to transmit data. Unfortunately, under the present television broadcasting system, the frequency bandwidth allocation favors video and audio with only a small amount dedicated to data services. Accordingly, the amount of data that can be transferred via the forward channel is very limited and downloading multiple graphics, which are a mainstay of today's Web pages, would thus be unacceptably slow given the limited bandwidth. Moreover, even if Internet content were able to be provided to a user and displayed on a television set, there is often a very limited or no return channel capability, that is, the client is unable, for example, to communicate back to a Web server to request a Web page. Yet further, Web pages are designed for displaying on PC monitors, not television sets. Thus, displaying such a page on a television screen generally results in poor image quality and navigating around the page and accessing the hypertext links for a page designed for display on a PC is nearly impossible.
The problem of limited bandwidth is often further exacerbated by the requirement of a low-cost client. In a broadcast marketing paradigm, these clients are often distributed by a broadcast service provider and leased or sold to viewers and thus it is imperative to minimize the costs of these clients. This can be accomplished by configuring the client with a low-cost CPU (i.e. slow) which may be able to perform only 2-6 million instructions per second ("MIPS"). In contrast, a CPU performing at 180 megahertz in a typical PC today, like the PowerPC, is able to perform around 50-70 MIPS, or higher. To further reduce costs, the client is usually configured with a very small memory footprint in the area of 1-4 megabytes. This type of client is usually unable to effectively process the amount of data contained in a graphically intense Web page, and can not communicate with the Web server due in part to its lack of a return channel, much less run today's resource intensive Web browsers.
Although Internet access devices using a television set are available, such as WebTV's set-top box for instance, these systems require the use of a telephone line as in today's dial-up lines. This allows the Internet access device forward and return channels to the Internet with adequate bandwidth for data transfer. These devices are thus like a simplified PC and only use the television as a display device and do not solve the above problem of getting Internet content to a client constrained by memory, CPU requirements, a network with a limited forward channel and/or limited or no return channel.